Firstly you have to make the weapons, using a 3d package, then you must texture, then you must animate, the you must export then import.
look in the 'great 3d resource' thread at the top, and pick out a program. I recomend Milkshape since your just starting.
next model it, I suggest you look for a simple tut on the program first to ge the hang of it. Then google (because i dont have my primary pc working i cant give you links) weapon tuts for~~~ modeling program~~
then you need to uv map the model for the texture, imagine flattening out a cube into 'net' so when you fold the pieces it creates the cube. same priciple next you need to draw a pretty picture on it and apply it to your model
then you need to animate. Animation can be done be two ways,
the fisrt being poly/vert adjusting per frame, this is laboursome and tiring when you need to move a few thousand on the. So overall its a no go area
the second is bone ainmating, look down at your wrist and turn it, notice how everything moves together with the bone the centre? (if you dont call 999), the same princilple with this except you move the bones not the muscles (well with advanced tecniques you can, but i wont go into that)
then all you have to do is export and your sort of ready to go, weapons need some other properties for fpsc which i am unfamiiliar with.
Right thats pretty much all the basics done and explained. someone else can fill the in the blanks i grow weary of this.